Anti-rust oils



ANTIRUST OILS Edgar A. Dieman, Crown Point, and Philip H. Ravens- United States PatentC i croft, Munster, Ind, assi nors te Standard Oil Comfi chicagd, 111., a corporation of Indiana No Drawing.- Application September .23, 1952,

Serial No. 311,142

This invention relates as improvements "in rust 'preventive compositions and particularly to petroleum base rust preventives' for application to metal surfaces in thin, continuous films.

Typical of the coatings applied to metal surfaces for protection from rust are those comprising predominately petroleum products such as lubricating oils, paraflin oils, greases, etc. Rust reventives of this type have given satisfactory protection under some corrosion conditions but not under others. To improve the effectiveness of such compositions, the art suggests that the soaps of preferentially oil soluble sulfonic acid (i. e. mahogany acids) derived from fuming sulfuric acid treatment of petroleum oils be added thereto. U. S. Patents 1,630,101, 1,795,993, and 2,348,715, disclosing broadly the use of soaps or oil :soluble sulfonic acids derived from petroleum oils in such compositions, are typical of the art on compositions of that type.

We have now made the surprising discovery that highly effective and very economical rust preventive compositions may be prepared from solvent extracts resulting from the treatment of petroleum oils of lubricating oil viscosity range with solvents such as phenol, Chlorex (5,;8" dichlorodiethylether), etc. Further, it has been discovered that the effectiveness of such extracts under certain conditions is increased by the addition of mahogany soap or by acid treatment of the extract and that even greater protection is obtainable under some conditions when the extract is both acid treated and admixed with mahogany 'soap.

Such extracts often, are quite viscous and may require dilution with a suitable hydrocarbon solvent to enable their application in substantially continuous, thin films.

Whether an acid treated or untreated extract should be employed in a given situation and whether a mahogany soap should be added thereto depends to a large extent upon the particular corrosive conditions to which 'the metal is to be subjected. Thus, in outdoor exposure tests it has been found that although some advantage may be gained by employing an acid treated extract, such is ordinarily insufiicient to warrant that additional refinement. Further, the use of mahogany soaps in either acid treated or untreated extract, under the conditions encountered in certain outdoor tests, results in no particular improvement. On the other hand, 'inhumiditycabinet "tests the advantage of first acid treating the extract .is clearly demonstrated and even greater improvement results from the incorporation of mahogany soaps. The conditions employed and "the corrosive a mosphere to which the test plates are subjected in each of these tests are substantia'lly different, as will hereinafter be apparent, and are intended to simulate widely divergent corrosive conditions to which metals may be subjected.

Without 'being bound 'by any theory herein expressed or implied, it appears that the oil-solubility and polarity of the particular mahogany 's'oap's employed as well as the polarity of the -'extracts has a noticeable effect upon 2,771,371 Patented Nov. 20, 1956 properties of the ultimate composition. In general, it has been found that compositions which are either excessively polar or non-polar in character tend to be poorer in "rust preventive properties than a more intermediate (with respect to polarity) composition. Thus, for example, although any mahogany soap prepared in accordance herewith may be employed in combination with either treated 'or untreated extracts to give substantial protection, particular combinations of extracts and mahogany 'soaps tending to moderate the polarity of the mix have'indicated advantages. Thus, the polarity of the soaps, to name only those, in a. non-limiting way, which are particularly preferred and in descending order of their polarity, is as follows: sodium AA mahogany soap, sodium B mahogany soap, calcium A mahogany soap, and calcium B mahogany soap. The polarity appears to vary inversely with respect to the molecular weight or the maps. It has'been found, infaddition, that acid 'tre'atedextracts are less polar in nature than those which are untreated. The use of a more polar soap with a treated extract or a less polar soap with an untreated extraflchtherefor'e, has given the best results. Unexpected and unexplainable variations in the degree of effectiveness, "may "be encountered, howeven'and many factors,

I e. g. the nature of the surface to be protected, the condit'iohs'to which 'it willbe exposed, etc. affect the selectio of the combination of soap and extract.

The variousgrades of mahogany acids, from which the soapsreferred to above are derived, are produced in a manner wen known to the art, i. e. by fuming sulfuric acid treatment of petroleum fractions. The B mahogany acids are producedffrom the treatment of petroleum oils having a viscosity of from about '100 toabout 350 SSU or higher with from about 3 to "6 pounds of fuming acid per gallon of oil. The treated oil is extracted with a 50 to solution of ethyl alcohol in Water at about to about using a ratio of about one volume of aqueous alcohol for each four volumes of oil. The sulfonic acids may "be neutralized before or after extraction from the oil, egg. by contact with sodium hydroxide solution, and may be purified by further extraction with alcohol to remove salts and water. The mahogany A and AA soaps are prepared in a manner similar to that used for "B soa'ps but employing somewhat lower viscosity oils and lesser amounts of sulfuric acid. The mahogany A "soaps are slightly more soluble in water than are the B soaps and the grade display even greater wa r solubility and a definite decrease in oil solubility. Refereaee is made to 8. 2,533,700 and U. s. 2,348,715 wherein a more detailed discussion of the nature and preparation of different grades of mahogany acids and soaps is contained; Although described particularly with respect to sodium and calcium soaps other metal soaps, such as are mentioned in the above patents, may be employed herein. V

Extractes employed in accordance herewith are those resulting from the solvent treatment of petroleum oils to remove aromatics and other low V. I. compounds. Whereas the extracts of lubricating oils in general have given excellent protection under either outdoor or humidity cabinet tests, it has been found that those compositions derived from the more viscous base oils, particula'rly SAE 40, furnish the most effective rust preventives in outdoor tests. In general, extracts having a viscosity at 100 F. of from about 500 to 10,000 S. S. U. and

preferably from about 3,000 to about 10,000 S. S. U.

may be employed. Somewhat higher percentages of an inert organic diluent is preferably employed with the more viscous extracts than is necessary with a less viscous material in order to produce an ultimate rust preventive eenpesiueaersucu viscosity as will enable its being 3 readily applied to metal surfaces in thin, continuous films. With the less viscous extracts a diluent may be dispensed with if desired.

Solvents employed in the treatment of lubricating oils to remove aromatics and other materials having a low viscosity index are well known to the art; thus, for example, phenol, Chlorex 3,5 dichlorodiethylether), furfural, nitrobenzene, sulfur dioxide, and others have been employed for the purpose. The extracts (freed of solvent) obtained by the treatment of lubricating oils with these solvents are of substantially the same type for any given oil and may be employed in accordance herewith. Whereas extracts obtained by extraction of lubricating oils with either Chlorex or phenol are referred to specifically and particularly preferred, extracts resulting from extraction with the other solvents are likewise suitable. Mixtures of such extracts from different sources may also be employed.

The methods by which the above named solvents are employed to treat lubricating oils andthe manner in which the extracts are freed of solvent are well-known to the art and it is not intended that such be construed as part of the present invention. Typical examples of such extraction processes are illustrated by U. S. 1,860,- 823 which describes a phenol extraction process, U. S. 2,003,233 the extraction of a lubricating oil with Chlorex, U. S. 2,161,567 describing extraction with furfural, U. S. 2,251,474 teaching extraction with S02, etc. Mixtures of such solvents (e. g. U. S. 2,120,810 teaches S02 plus phenol) likewise may be employed.

With respect to the treatment of these solvent extracts with sulfuric acid, it is preferred that the extract itself be acid treated after solvent extraction has occurred. Some of the advantages of an acid treated extract may be obtained, however, when untreated extracts of previously acid treated oils are employed. Sulfuric acid of from about 92% to about 98% strength is preferably employed for the acid treatment of extracts in accordance herewith. About 0.5 pound to 3 pounds of acid per gallon of extract may be employed, preferably from about 1 to 2 pounds per gallon. The acid treatment may take place in the presence of a low boiling solvent such as propane, pentane, etc. Such solvent is removed completely before employing the oil in accordance herewith. Sludge formed is removed by settling before compounding the rust preventive.

Some extracts of the type described are viscous and ordinarily incapable, under normal temperature conditions, of being spread over a metal surface in a relative- 1y thin and continuous film. Accordingly, it is essential to cut their viscosity with a solvent-thinner such as a naphtha, kerosene, benzene, carbon tetrachloride, etc. Stoddard Solvent (sometimes referred to as Cleaners Solvent) a highly refined naphtha, boiling from about 300 F. to about 400 F., is particularly suitable for the purpose. Petroleum solvents, in general, boiling from about 200 F. to about 450 F. are particularly desirable for the purpose.

In addition to the mahogany soap, solvent extract, and inert organic diluent, the improved rust preventive composition preferably contains a small amount of a compound which comprises a mixture of aliphatic oxygen containing compounds of petroleum origin. These are preferably obtained by controlled oxidation of pure hydrocarbons or mixtures thereof, such as the hydrocarbons occurring in or associated with petroleum oils, in liquid phase at an elevated temperature and under super-atmospheric pressure. These aliphatic compounds contain a mixture of substantial quantities of alcohols, ketones, alcohol-ketones, lactones and esters together with some unoxidized hydrocarbons. The method of obtaining these compounds and the compositions thereof are described in U. S. Patents, 2,090,768, 2,090,769 and 1,863,004 as Well as others. Products Of this WP? t l? marketed under the trade name of Alox"; compounds designated as Alox 350 and Alox 600 are particularly desirable for this purpose and substantially contribute to the lubricity of the rust preventive compositions as well as, to some extent, enhancing rust preventive properties of the composition. A certain amount of lubricity is desirable in rust preventives employed to coat certain types of metal surfaces. Thus, for example, in steel strapping employed to bind bales of paper, cotton, or boxing of materials, etc., it is necessary that the ends of the strap, which are in contact as the binding is tightened, slide over each other relatively easily with a minimum of friction. The composition of the present invention serves the dual purpose in such cases of preventing rust and lubricating the surfaces.

Rust preventive compositions of the present invention may contain the above described components in the following approximate proportions:

1 Whereas a diluent is not essential it is ordinarily desirable to employ same in conjunction with such a composition. The diluent should, in any event, comprise not more than about and preferably from about 50 to 75% by weight of a diluted rust preventive composition.

2 Based upon oil-tree soap (petroleum mahogany soaps as recovered by method referred to above ordinarily contain from about 40 to about 70% oil by weight).

3 Mahogany Soap" as employed in the above formula and in the appended claims may include only one or a plurality of difierent grades of preferentially oil-soluble solfonate, e. g. Sodium B and Calcium A, etc.

The data set forth in Table l were obtained in humidity cabinet tests. In such tests, polished or sand blasted cold rolled S. A. E. 1020 steel panels, 2 x 3 x A; were suspended in an atmosphere of humidity at 100 F. in a special cabinet and the time of initial corrosion of the panels is noted. The humidity cabinet is pro- TABLE 1 Humidity cabinet test 1 Mahogany Soap Employed as Additive Coating on Panel None Soda Soda Calcium A B A Hours to Initial Rust None 8 Chlorex Extract of SAE 40 Oil 24 135 135 Acid Treated Chlorex Extract of SAE 40 Oil 24 135 279 207 Chlorex Extract of SAE 20 Oil 24 141 480 21 Acid Treated Chlorex Extract of SAE 20 Oil 24 135 471 207 Phenol Extract of SAE 10 Oil 24 69 69 Acid Treated Phenol Extract of SAE 10 Oil 24 189 166 213 Chlorex Extract of Acid Treated SAE 40 Oil 24 141 69 717 Chlorex Extract 2 of Acid Treated SAE 20 Oil 24 165 189 309 Chlorex Extract of Acid Treated SAE 10 Oil 24 237 333 189 1 Test conducted as described above in specification; panels were dipped in composition comprising 68% Stoddard Solvent, 30% extract and 2% sulfonate (oil free basis).

1 Note that base oil was acid treated prior to extraction.

vided with heating units and thermal regulators for automatic temperature control. A water level of about six inches is maintained in the bottom of the cabinet to give approximately 100% humidity at all times. The steel panels are coated by dipping into the rust preventive material, dried overnight, and are suspended by glass hooks from a revolving stage in the humidity cabinet. From 1 to1.5 complete changes of saturated air per hour are provided in the cabinet. All extracts employed in tests hereinafter set forth were from dewaxed oils. Those referred to as being acid treated were contacted with one pound of 96% H2804 per gallon of extract.

As may be observed in Table l, the compositions of the present invention give substantial protection from corrosion under severe conditions as compared with uncoated panels or extracts without mahogany soaps therein. In general, under the conditions of the tests, the acid treated extract or extract resulting from an acid treated stock provides more protection than a composition derived from an untreated extract. In Table 2 is shown the improvement obtainable by an increase in soap content and the use of a combination of mahogany soaps selected to moderate the polarity of the mixture.

TABLE 2 1 Panels were dipped in composition comprising 70% Stoddard Solvent, i095 girtract, 4% calcium soap of Alox 600 and 6% sulionate (oil-tree asis Although the Alox 600 soap employed in the above tests appears to have a beneficial eifect upon the rust'preventive properties of the composition it is added primarily to impart lubricity to the composition.

In Table 3 are shown the results of outdoor exposure tests in which the eifectiveness of untreated extracts is shown to be at least as high (within the limits of observable difference) if not higher than treated extracts. Other outdoor tests in which the time of exposure was somewhat greater (and which are therefore not entirely comparable), indicated that incorporation of mahogany soaps in either treated or untreated extracts resulted in no improvement.

TABLE 3 Outdoor exposure tests 1 Coating 1 on panel None-. Phenol Extract of SAE 10 Oil Acid Treated Phenol Extract of S E 10 O Phenol Extract of SAE 20 Oil Acid Treated Phenol Extract of SAE 2D Oil.. Phenol Extract of SAE 40 Oil Acid Treated Phenol Extract of SAE 40 Oil Chlorex Extract of Acid Treated SAE 10 Oi Chlorex Extract of Acid Treated SAE 20 0i. Chlorex Extract of Acid Treated SAE 40 01 SAE 10 Oil (raffinate from phenol extraction}--. SAE 20 Oil grafimate from phenol extraction BAE 40 Oil raflinate from phenol extraction) 1 N o mahogany soap employed.

BAE 1020 sandblasted anels placed at about a 60 angle and given southern e osure on b ding root for 14 days during December and January in ammond, Indiana; panels were dipped in compositions comprislng l volume extract and 4 volumes naphtha and. dried overnight bolero beginnlnz test.

Percentages given in the above specification and the appended claims are on a weight basis unless otherwise specified.

Having thus particularly described our invention, what we claim as novel and desire to protect by Letters Patent is defined by the following claims:

1. The method of treating ferrous metal surfaces which are normally exposed to atmospheric air and moisture to prevent rust formation .on said surfaces, which method comprises applying to said ferrous metal surfaces a thin film of a slushing oil consisting essentially of a phenol extract of a petroleum oil of lubricating oil viscosity, from about 1% to about 30% of mahogany soap, and from about 1% to about 10% of a mixture of saturated aliphatic oxygen containing compounds including alkyl esters, lactones, ketones, alcohols, and alcohol ketones, said saturated aliphatic oxygen containing compounds being obtained by partial oxidation of petroleum hydrocarbons.

2. The method of claim 1 wherein said phenol extract has been treated with a sulfuric acid of from about 92% to about 98% strength in an amount of from about 0.5 to about 2.5 pounds of acid per gallon of extract.

3. The method of claim 1 wherein the slushing oil is admixed with from about 1% to of an inert hydrocarbon diluent comprising a petroleum naphtha fraction having a boiling range between about 200 F. and about 450 F. and said diluent is vaporized from the slushing oil film after it is applied to said surfaces so that the extract is the sole hydrocarbon component of the final slushing oil film.

4. A composition for preventing rust formation on ferrous metal surfaces which are normally exposed to atmospheric air and moisture, which composition consists essentially of a phenol extract of a petroleum oil of lubricating oil viscosity, from about 1% to about 30% of mahogany soap, and from about 1% to about 10% of a mixture of saturated aliphatic oxygen containing compounds including alkyl esters, lactones, ketones, alcohlOlS, and alcohol ketones, said saturated aliphatic oxygen containing compounds being obtained by the partial oxidation of petroleum hydrocarbons.

5. The composition of claim 4 in admixture with from about 1% to about 85% of an inert hydrocarbon diluent comprising a petroleum naphtha fraction having a boiling range between about 200 F. and about 450 F.

6. The composition of claim 4 in which said phenol extract has been treated with a sulfuric acid of from about 92% to about 98% strength in an amount of from about 0.5 to about 2.5 pounds of acid per gallon of extract.

References Cited in the file of this patent UNITED STATES PATENTS 2,247,475 Bray et al. July 1, 1941 2,279,001 Matheson et al. Apr. 7, 1942 2,305,358 Read Dec. 15, 1942 2,348,715 Adams et al. May 16, 1944 2,383,033 Wade et al. May 16, 1944 

4. A COMPOSITION FOR PREVENTING RUST FORMATION ON FERROUS METAL SURFACES WHICH ARE NORMALLY EXPOSED TO ATMOSPHERIC AIR AND MOISTURE, WHICH COMPOSITION CONSISTS ESSENTIALLY OF A PHENOL EXTRACT OF A PETROLEUM OIL OF LUBRICATING OIL VISCOSITY, FROM ABOUT 1% TO ABOUT 30% OF MAHOGANY SOAP, AND FROM ABOUT 1% TO ABOUT 10% OF A MIXTURE OF SATURATED ALIPHATIC OXYGEN CONTAINING COMPOUNDS INCLUDING ALKYL ESTERS, LACTONES, KETONES, ALCOHOLS, AND ALCOHOL KETONES, SAID SATURATED ALIPHATIC OXYGEN OXIDATION OF PETROLEUM HYDROCARBONS. 